Moreover, while it is well established that prolonged fasting—unlike chronic caloric restriction—reduces circulating IGF-1 levels in humans [13,14,15,16], the effects of prolonged fasting on pathways such as insulin/IGF1/mTOR, which are crucial for DNA repair, cell proliferation, cancer suppression, and ageing, have not been thoroughly investigated in human studies [8,17,18,19]. Here, IGF1 is linked to cancer.